Jet ejector lubricant return means for a refrigeration compressor



C. B. HAMILTON I'AL JET EJECTOR LUBRIC Oct. 18, 1960 2,956,730

ANT RETURN MEANS FOR y A REFRIGERATION COMP SSOR Filed June 16,' 1

FIG. 4 CLARK B. HAMILTON I INWOOD A. PICKLE INVENTORS MM/3M UnitedStates Patent() JET EJECTOR LUBRICANT RETURN MEANS FOR A REFRIGERATIONCOMPRESSOR Clark B. Hamilton, Wethersfield, Conn., and Linwood A.

Pickle, Holyoke, Mass., assignors to Worthington Corporation, Harrison,NJ., a corporation of Delaware Filed June 16, 1958, Ser. No. 742,111

8 Claims. (Cl. 2311-58) This invention relates -generally torefrigeration compressors either of the open or hermetically sealed typeand more particularly to a means for returning lubricant from the motorcompartment to the main crankcase of the refrigeration compressor.

Reciprocating compressors used in modern refrigeration cycles aregenerally driven by a constant speed electric motor.

In many refrigeration cycles utilizing such compressormotor units, therefrigerant will be dichlorodifluoromethane or some similar type ofrefrigerant which refrigerants are miscible with the lubricant fluidused for lubricating the reciprocating compressor bearings and othermoving parts. Accordingly, these compressormotor units are constructedso that the motor compartment which communicates with the suctionmanifold will be separated from the main crankcase for the compressorfor the following purposes:

(a) To suppress foaming of oil (b) Prevent oil and refrigerant slugging,and

(c) Permit filtering of the oil entrained in the returning refrigerantgas and any oil that collects in the motor compartment, either from thereturning refrigerant or from leakage lthrough the crankshaft bearing isreturned to the main crankcase by some suitable means.

Accordingly, it is an object of the present invention to provide aninexpensive positive means for returning lubricant from the motorcompartment to the main crankcase reservoir by utilizing an ejector incombination with the normal lubricant pressure which ejectorcommunicates with the motor compartment at the oil level desired anddischarges into the main crankcase reservoir.

Further objects and advantages of the invention will become evident fromthe following description with reference to the accompanying drawings,in which:

Figure 1 is a vertical section partly in side elevation showing theinvention.

Figure 2 is an enlarged view of the ejector means taken on line 2-2 ofFigure 1.

Figure 3 is an enlarged vertical section of the ejector means showing itconnected to the partition between the motor compartment and the maincrankcase.

' Figure 4 is a fragment of a compressor-motor unit `and an axiallydisposed bulkhead 3 into a motor compartment 4, a crankcase compartment5 and a suction manifold 6 which communicates freely with the motorcompartment.

A crankshaft 7 supportably mounted in bearings 8 and `9 disposedrespectively in the end of the casing 1 and in the partition 2 isprovided with a jackshaft as at 10 A 2,956,730 Patented Oct. 18, 1960ice which extends through the partition into the motor compartment 4.Fixedly connected about the jackshaft 10 is an armature 11 which isdisposed relative a stator 12 mounted on the inner wall of the motorcompartment section of the casing 1 by means of a stop-shoulder 13 whichholds it in longitudinal position. An adaptor hub 14 is detachablyconnected to the casing for easy access to the armature and stator,respectively, and to form the outboard portion of the motor compartment4.

Current is passed to the coil 15 of the stator 12 by means of thecurrent conducting lines 16, 17 and 18, in turn connected to a source ofpower, not shown, in the manner well known in the art.

When current is passed through the stator the armature is caused torotate and since it is ixedly mounted on the jackshaft it also rotatesthe jackshaft 10 and the crankshaft 9.

Connected to the crankshaft is a connecting rod 20 having a piston 21 atthe end remote from the crankshaftconnected end. The piston is slidablydisposed in a cylinder 22 formed transversely of the casing 1 and thelaxial partition 3 along an imaginary radial line perpendicular to thecenterline of the crankshaft. The piston is reciprocated in the cylinderon rotation of the crankshaft. It will be understood that while only onecylinder is shown that the present invention is equally applicable to amulti-cylinder compressor-motor unit.

The cylinder opens on the outer wall of the casing 1 and mounted aboutthis opening is the head 23 which has `a suction valve'24 and adischarge valve 25 formed therein to provide communication between thecylinder and a suction inlet chamber 26 and also the cylinder and vadischarge outlet chamber 27. The suction inlet chamber 26 `communicatesthrough ports 28 and 29 with the suction manifold 6 so that when thepiston 21 is recipv-rocated in the cylinder fluid from the motorcompartment 4 and suction Imanifold will pass into the suction chamberand through the suction valve on the downward or outward stroke of thepiston land from the cylinder through the discharge valve to thedischarge outlet chamber on upward or inward stroke of the piston.

Lubrication system The bearings and other moving parts of thecornpressor relating to the crankshaft and piston assembly arelubricated by any suitable lubrication system.

Thus, in the present form of the invention the crankcase is shown ashaving lubricant 30 disposed in a reservoir generally designated 31formed at the lower portion of the crankcase. This lubricant is pumpedfrom the reservoir by means of any suitable type of rotary pumpgenerally designated 32 which takes its suction through the suctioninlet'33 and suction line 34 having a ilter 35 about the opening thereofwhich is disposed at the lowest portion of the reservoir. The lter isutilized to prevent sludge and other foreign particles from passing withthe lubricant uid into the suction inlet for the pump. The pump isprovided with a discharge outlet 36 which communicates through a commonduct or passage 37 with the respective transverse passages 38 and 39which feed the bearings 7 and 8, respectively. Other transverse passages40 throw fluid onto the connecting means for the connecting rod 20 andother moving parts of the crankcase and piston assembly, all of which isclearly shown in Figure 1 of the drawings.

This form of the invention as above described is known in the .art andis described to show the conventional arrangement to which the presentinvention is applied. As can be visualized through Figure 1, thelubricant level shown in the crankcase compartment 5 is higher than thatin the motor compartment 4. Lubricant is continuously collected in themotor compartment from at least two sources, namely, the returningrefrigerant and leakage from the bearing 8. Due to blowby whichmaintains the pressure in the crankcase above that of the motorcompartment, it is necessary that some positive means-be provided forreturning the uid from the motor compartment 4 to the reservoir 31formed in the crankcase compartment.

Ejector means This is accomplished by means of an ejector generallydesignated 41 which has its suction inlet 42 connected to the partition2 so that the inlet is disposed at that predetermined point in thepartition for maintaining the level of collected oil in the motorcompartment at the desired level. The ejector is clearly shown inFigures 2 and 3 of the drawings as comprising a body portion 50 having anozzle 51 disposed anterior of the suction chamber 52 which communicateswith the suction inlet42 for the ejector. The suction chambercommunicateswith the discharge outlet 53 which is disposed as shown inFigure l to discharge motive fluid onto the movingpartsof the crankcaseand piston assembly. The lmotive fluid is de livered to the ejector 41by means of a feedline 54con nected by any suitable connecting means `55to thepump 32 at one end and at the other end by any suitable connectingmeans 56 to the nozzle end of the body portion S0 of the ejector 41.Thus, means are-provided to deliver motive fluid through the nozzle V51into the diS- charge chamber 53 of the ejector in the manner well knownin the art.

Since the compressor motor unit forms a part of a refrigerant cycle,Figure l also shows that the refrigerant uid is returned to the unitthrough a line 60 which com municates with an opening 61 formed in theadapter 14.

This point in the motor compartment is on the side of the motor remotefrom the ejector means 41. Accordingly, the returning lubricant in orderto reach the suction manifold 6 must pass through the motor to the lowerpressure side of the motor and thence out of the motor compartment intothe suction manifold 6, passages 28 and 29, suction chamber 26, andsuction valve 24 to the cylinder 22. In passing through the motor itacts to cool the motor and in addition the drop in pressure will causelubricant entrained therein to separate out in the motor compartment,which uid is collected in the lower portion of the motor compartment asshown in Figure l.

Operation In operation, when current is passed to the stator and thecrankshaft made to rotate as above described, not only will the piston21 be reciprocated in the cylinder 22 but the rotary pump 32 will alsorotate.

Rotation of the pump 32 passes fluid through the suction line 34, thesuction inlet 33 through the pump 32 and then to its discharge outlet36, in turn connected through lines 37, 38 and 39 to the respectivebearings 7 and 8 and other moving parts. In addition, the pumpedlubricant passes through connection 55, line 54 to the nozzle end of theejector 41 where it is discharged through the nozzle as the motive lluidfor entraining and moving the collected lubricant from the motorcompartment 4 through the suction inlet 42 to the suction chamber 52whence it is discharged through the discharge chamber 53 back to thereservoir 31 formed in the crankcase compartment 5.

Although the above described form of this invention shows the ejectorasdisposed in the crankcase compartment, it is believed clear to thoseskilled in the art that by using exterior lines, the ejector means couldbe disposed on the outside of the motor compartment at the desired pointfor maintaining the level of the collected fluid and still discharge itslubricant into the reservoir formed in the crankcase compartment without`departing from the scope of the present invention. A Y' Modified formof ejector means 'Figure 4 shows a fragment of a compressor-motor unitsimilar to that above described. It differs, however, in that thepartition 2 is modified to provide means for forming an ejectorgenerally designated 61 therein and to provide a passage 62 whichcommunicates through annular chamber '63 with the lubricant passagewhich feeds the main bearing designated 8 in the form of the inventionshown in Figure l. All remaining portions of this illustrated form ofthe invention are deemed to be identical with that above described andaccordingly they have not been illustrated further.

The ejector means 61 includes a suction chamber -64 having a suctioninlet 65 extending into the motor compartment 4. The suction inlet is inthe form of an elongated bent pipe which cau be adjusted to extend apredetermined point in the motor compartment at which it is desired tomaintain the level of collected lubricant fluid.

A nozzle element 66 is mounted inthe suction chamber 64 to communicatewith the passage 62 for receiving the motive fluid for operating theejector means.

Motive fluid passed from the passage 62 to the nozzle elements 66 isdischarged through a discharge chamber 67 into the reservoir portion 31of the crankcase 5.

Since the discharge chamber 67 also is in communication with the suctionchamber 64 when the fluid is passed to the discharge chamber it `acts tomove the eollected lubricant in the motor compartment 4 by positivedifferential pressure from the motor compartment to the suction chamberand thence through the discharge chamber back to the reservoir in thecrankcase 5.

In either form of the invention the ejector means cre ates a positivedifferential pressure and it acts to maintain the level of collectedlubricant in the motor compartment at whatever predetermined point itisset inthe partition 2 relative the level of the lubricant in the motorcompartment.

It will be understood that the invention is not to be limited to thespecific construction or arrangement of parts shown but that they may bewidely modified within the invention defined by the claims.

What is claimed is:

l. In a compressor-motor unit to be used in `a refrigerant cycle, acasing, a partition in said casingforming a motor compartment and acrankcase compartment, a lubrication system for said unit, ejector meanshaving an inlet and an outlet operatively connected to-said` lubricationsystem to receive `motive fluid therefrom, said ejector meanscommunicating with themotor compartment at a predetermined point formaintaining the `de" sired level of collected lubricant in said motorcompartment when the refrigerant cycle is in operation.

2. In a compressor-motor unit to be used in arefrigerant cycle, acasing, a partition 4in said casing forming a motor compartment `and acrankcase compartment, means in said casing forming a suctionimanifold,communicating with said motor compartment, `a lubrication system fordelivering lubricant fluid under pressure to the moving parts of saidcompressonejector means having an inlet and an outlet operativelyconnected to said lubrication system -to receive motive fluid therefrom,said ejector means having a suction inlet, and means connecting thesuction inlet of said ejector means to the motor compartment at apredetermined point for maintaining the desired level of collectedlubricant in said motor ,compartment when the refrigerant cycle is inoperatlon.

3. In a compressor-motor unit to be used in a refrigerant cycle, acasing, a partition in said casingforming a motor compartment and acrankcase compartment, means in said casing forming `a suction manifoldcommunicating with said motor compartment, ailubrication system for thecompressor portion of saidunitincluding Va pump Afor deliveringlubricant under pressure, fejector means including a suction inlet,means connecting said suction ,inlet with the motor compartment at a`predetermined point for maintaining the `desired level of collectedlubricant in said motor compartment, inlet means on said ejectorproviding communication between said ejector means and said pump to passmotive fluid to said ejector means when the refrigerant cycle is inoperation, and outlet means on said ejector for returning mixed motivefluid and collected lubricant to said lubricator system.

4. In a compressor-motor unit to be used in a refrigerant cycle, acasing, a partition in said casing forming a motor compartment and acrankcase compartment, means in said casing forming a suction manifoldcommunicating with said motor compartment, a lubrication system for themoving parts of the compressor portion of said unit, and ejector meansincluding a nozzle element, inlet means connecting said nozzle elementto the lubrication system to pass motive fluid thereto, said ejectormeans having a suction inlet disposed to communicate with said nozzleelement, means connecting said suction inlet to the motor compartment ata predetermined point for maintaining the desired level of collectedlubn'- cant in said motor compartment when the refrigerant cycle is inoperation, and said ejector having outlet means for returning lubricantto said crankcase.

5. In a compressor-motor unit to be used in a refrigerant cycle, acasing, a partition in said casing forming a motor compartment and acrankcase compartment, means in said casing forming a suction manifoldcommunicating with said motor compartent, a lubrication system adaptedto deliver lubricant under pressure to the moving parts of thecompressor portion of said unit, ejector inlet mean-s disposed in saidcrankcase compartment, means on said ejector for connecting said ejectormeans to the pump to pass motive fluid thereto, said ejector meanshaving a suction inlet connected through the partition at apredetermined point for maintaining the desired level of collectedlubricant in said motor compartment when said refrigerant cycle is inoperation, and said ejector having an outlet means for returning mixedmotive fluid and collected lubricant to said lubrication system.

6. In a compressormotor unit to be used in a refrigerant cycle, acasing, a partition in said casing forming a motor compartment and acrankcase compartment,

means in said casing forming a suction manifold com municating with saidmotor compartment, a lubrication system adapted to deliver lubricantunder pressure to the moving parts of said `compressor portion of theunit, ejector means disposed in said partition, inlet means `and outletmeans providing communication between said ejector means and thelubrication system to pass motive fluid to the ejector means, saidejector means having a suction inlet disposed to communicate with themotor compartment at a predetermined point for maintaining the desiredlevel of collected lubricant in said motor compartment when therefrigerant cycle is in operation.

7. In a compressor-motor unit as claimed in claim 4 wherein said unitincludes a crankshaft, a connecting rod connected to said crankshaft,and said ejector means is disposed in the c-rankcase compartment todischarge lubricant at approximately the point of connection between thecrankshaft and the connecting rod.

8. In a compressor-motor unit for a refrigerant cycle, a casing, apartition in said casing forming a motor compartment and a crankcasecompartment, a motor in said motor compartment dividing the compartmentinto an inboard end and an outboard end, means in said casing forming -asuction manifold in communication with the inboard end of said motorcompartment, means for returning refrigerant from said refrigerant cycleto the outboard end of said motor compartment, a lubrication system forpassing lubricant under pressure to the compressor portion of the unit,ejector means having an inlet and an outlet operatively connected tosaid lubrication system for receiving motive fluid therefrom, saidejector means connected to the inboard end of the motor compartment at apredetermined position to maintain collected lubn'- cant in the motorcompartment at la desired level and to maintain a pressure differentialbetween the inboard and outboard end of said motor compartment wherebyreturning refrigerant will pass through the motor to the suctionmanifold when the refrigerant cycle is in operation.

References Cited in the tile of this patent UNITED STATES PATENTS

